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# RUN: llc -run-pass postrapseudos -mtriple=i386-apple-macosx -o /dev/null %s 2>&1 | FileCheck %s
# Verify that we correctly save and restore eax when copying eflags,
# even when only a smaller alias of eax is used. We used to check only
# eax and not its aliases.
# PR27624.
--- |
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
define void @foo() {
entry:
br label %false
false:
ret void
}
...
---
name: foo
allVRegsAllocated: true
isSSA: false
tracksRegLiveness: true
liveins:
- { reg: '%edi' }
body: |
bb.0.entry:
liveins: %edi
successors: %bb.1.false
NOOP implicit-def %al
; The bug was triggered only when LivePhysReg is used, which
; happens only when the heuristic for the liveness computation
; failed. The liveness computation heuristic looks at 10 instructions
; before and after the copy. Make sure we do not reach the definition of
; AL in 10 instructions, otherwise the heuristic will see that it is live.
NOOP
NOOP
NOOP
NOOP
NOOP
NOOP
NOOP
NOOP
NOOP
NOOP
NOOP
NOOP
NOOP
; Save AL.
; CHECK: PUSH32r killed %eax
; Copy EDI into EFLAGS
; CHECK-NEXT: %eax = MOV32rr %edi
; CHECK-NEXT: %al = ADD8ri %al, 127, implicit-def %eflags
; CHECK-NEXT: SAHF implicit-def %eflags, implicit %ah
%eflags = COPY %edi
; Restore AL.
; CHECK-NEXT: %eax = POP32r
bb.1.false:
liveins: %al
NOOP implicit %al
RETQ
...
|
